Optical microscanning system and method with embedded scannable photo-pumped light source

Abstract

An optical microscanning system for selectively emitting a highly coherent, collimated, and monochromatic beam of light ( 122 ) in a desired trajectory and selectively redirecting the trajectory within a scan field. The system includes a fixed light source ( 112 ) of substantially coherent, collimated, and monochromatic light ( 118 ) and an optically pumped light source ( 120 ) of highly coherent, collimated, and monochromatic light ( 122 ). The optically pumped light source ( 120 ) is optically pumped by the fixed light source ( 112 ). The optically pumped light source ( 120 ) can selectively redirect its light output ( 122 ). Also, a method of manufacturing such an optical microscanning system. A cavity is etched ( 156 ) in a base substrate. Two electrodes are provided ( 158 ) at the cavity floor. A second layer is provided ( 160 ) over the mouth of the cavity. A mirror layer is bonded ( 162 ) onto the second layer. Spacers are etched ( 164 ) through the mirror layer and second layer to define a substrate section ( 165 ). The mirror layer is etched to define a mirror ( 166 ).

1 . An optical microscanning system for selectively emitting a highly coherent, collimated, and monochromatic beam of light in a desired trajectory and selectively redirecting the trajectory within a scan field, the system comprising: 
 a fixed light source of substantially coherent, collimated, and monochromatic light;    an optically pumped light source of highly coherent, collimated, and monochromatic light;    wherein the optically pumped light source is relatively positioned and configured to be optically pumped by the highly coherent, collimated, and monochromatic light output of the fixed light source; and    wherein the optically pumped light source has a scan range within which it is adapted to be scannably reoriented in order to selectively redirect the highly coherent, collimated, and monochromatic light it emits.    
   
   
       2 . The optical microscanning system according to  claim 1 , wherein the fixed light source comprises a vertical cavity surface emitting laser.  
   
   
       3 . The optical microscanning system according to  claim 2 , wherein the vertical cavity surface emitting laser comprises stacks of aluminum gallium arsenide and gallium arsenide substrates and is configured to emit a beam of light to which silicon is transparent.  
   
   
       4 . The optical microscanning system according to  claim 3 , wherein the vertical cavity surface emitting laser further comprises indium gallium arsenide and is configured to emit a beam of light having a 1.3 micron wavelength.  
   
   
       5 . The optical microscanning system according to  claim 1 , further comprising a scanning mechanism defining the scan range of the optically pumped light source according to a single axis of reorientation.  
   
   
       6 . The optical microscanning system according to  claim 5 , wherein the scanning mechanism further defines the scan range of the optically pumped light source according to a second axis of reorientation.  
   
   
       7 . The optical microscanning system according to  claim 1 , further comprising a spacer located between the fixed light source and the optically pumped light source for fixing the relative positions of the fixed and optically pumped light sources.  
   
   
       8 . The optical microscanning system according to  claim 7 , wherein the spacer comprises a material transparent to the substantially coherent, collimated, and monochromatic light emitted by the fixed light source.  
   
   
       9 . The optical microscanning system according to  claim 7 , 
 wherein the spacer comprises a material opaque to the substantially coherent, collimated, and monochromatic light emitted by the fixed light source; and    wherein the spacer defines a hole through which the substantially coherent, collimated, and monochromatic light emitted by the fixed light source can pass to pump the optically pumped light source.    
   
   
       10 . A bank of optical microscanning systems, comprising: 
 a plurality of optical microscanning systems according to  claim 1;  and    wherein each optical microscanning system is configured to emit a highly coherent, collimated, and monochromatic light having a different wavelength.    
   
   
       11 . The bank of optical microscanning systems according to  claim 10 , wherein the plurality of optical microscanning systems according to  claim 1  comprises: 
 three optical microscanning systems according to  claim 1 , wherein a first system is configured to emit red light, a second system is configured to emit green light, and a third system is configured to emit blue light.    
   
   
       12 . The optical microscanning system according to  claim 1 , adapted for countering terrorism by detecting a known compound, 
 wherein the optically pumped light source is adapted to emit a beam of ultraviolet radiation selected for the property of causing the known compound to emit a known characteristic sheen in optical response to being struck by the selected ultraviolet radiation.    
   
   
       13 . A method of manufacturing an optical microscanning system for selectively emitting a highly coherent, collimated, and monochromatic beam of light in a desired trajectory and selectively redirecting the trajectory within a scan field, the method comprising the steps of: 
 etching a cavity in a base substrate, wherein a fixed light source is provided at the floor of the cavity;    providing two electrodes at the floor of the cavity for electrically pumping the fixed light source;    providing a second layer over the mouth of the cavity;    bonding a mirror layer onto the second layer;    etching spacers through the mirror layer and second layer to define a substrate section of the second layer and enable the substrate section to move with a desired degree of freedom within a scan range; and    etching the mirror layer to define a mirror.    
   
   
       14 . The method of manufacturing an optical microscanning system according to  claim 13 , wherein the step of etching the cavity in the base substrate comprises the step of: 
 reactive ion etching the cavity in the base substrate.    
   
   
       15 . The method of manufacturing an optical microscanning system according to  claim 13 , further comprising the step of: 
 providing two isolators at the floor of the cavity for isolating the electrodes.    
   
   
       16 . The method of manufacturing an optical microscanning system according to  claim 15 , wherein the step of providing two isolators comprises the step of: 
 providing two isolators composed of silicon dioxide placed by plasma enhanced chemical vapor deposition.    
   
   
       17 . The method of manufacturing an optical microscanning system according to  claim 16 , wherein the step of providing two electrodes comprises the step of: 
 providing two electrodes composed of polysilicon placed upon the isolators by means of plasma enhanced chemical vapor deposition.    
   
   
       18 . The method of manufacturing an optical microscanning system according to  claim 13 , wherein the step of etching the cavity in the base substrate comprises the step of: 
 etching the cavity in the base substrate to a selected depth based on the anticipated effects of an air film within the cavity on the movement of the mirror in order to enable accurate and precise movement of the mirror.    
   
   
       19 . The method of manufacturing an optical microscanning system according to  claim 13 , further comprising the step of: 
 etching the mirror layer and the second layer to define hinges within the second layer that are connected to the substrate section to enable the substrate section to scan according to an axis coaxial with the hinges.    
   
   
       20 . The method of manufacturing an optical microscanning system according to  claim 19 , wherein the substrate section and the hinges are composed of single-crystal phosphorous-doped silicon.